The association between silica exposure, silicosis and tuberculosis: a systematic review and meta-analysis

BMC Public Health

Table 5 Tuberculosis risk/odds by silica exposure, dustiness of occupation or exposure duration, controlling for silicosis

Sherson 1990 [47]	Hnizdo 1998 [49]	Corbett 1999 [50]	Corbett 2000 [51]	Yarahmadi 2013 [54]
SIR or RR ^a (95% CI)	RR (95% CI)	OR 95%CI)	RR (95%CI)	OR (95% CI)
Silicotics excluded.	White miners, > 10 years’ exposure; adjusted for silicosis ^b, age, smoking.	Adjusted for silicosis, age, HIV.	Adjusted for silicosis, age, HIV.	Silicotics excluded. No other adjustment.
Binary or summary effect measures
Duration of employment (yr), (RR) < 15: 1.00 > 15: 2.39 (0.96, 6.44)	Per 8 mg-yr/m^{3 c} 1.95 (1.58, 2.2)	Occupation (dusty job at diagnosis) No: 1.00 Yes 1.00 (0.62, 1.63)	Occupation (underground vs surface) No: 1.00 Yes: 2.00 (1.11, 3.33)	Silica exposure None: 1.00 Any: 2.85 (1.13, 3.42)
Dose-response
Duration of employment (yr), SIR General male population: 100 0.15–14.5: 133 (57, 262) 15.0–24.5: 128 (26, 375) > 25: 353 (130, 768)	Cumulative dust (mg-yr/m³) quartile 1: 1.00 2: 1.51 (0.78, 2.91) 3: 2.35 (1.28, 4.32) 4: 3.22 (1.75, 5.90)	Duration of employment (yr) < 10: 1.00 10–14: 1.9 (1.07, 3.36) 15–19: 4.4 (2.45, 7.75) > 20: 3.6 (1.84, 7.12)	Duration of exposure (yr) 0–4: 1.8 (0.9, 3.5) 5–9: 1.00 10–19: 1.6 (1.0, 2.5) > 20: 1.3 (0.8, 2.3)
Duration of employment (yr), (RR) 0.05–14.5: 1.00 15–24.5: 1.44 (0.38, 5.43) > 25: 3.9 (1.36, 11.23)^a

RR relative risk or rate ratio (see Table 1), SIR standardised incidence ratio, CI confidence interval, RR odds ratio
^a RR estimated for this review comparing silicotics with non-silicotics in the same cohort
^b Adjustment for radiological silicosis. Analysis by adjustment for radiological or autopsy silicosis yielded similar findings
^c RR for 1 mg-yr/m³ = 1.10 (1.06, 1.13). RR scaled to interquartile range (see Table 1 of the publication) of 10–17.99 mg-yr/m³ (as used in [58])

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